There is nothing intrinsically wrong with a relationship such as this, but what about children? Let’s say you get married in two years and have your first child the next year. She will be 45. There are increased risks of various problems when the mother is in that age cohort. Then a second child? Something to consider.
Also, I’m sure you’ve already done the math, but when you are 30, she’ll be 52. When you’re 40, she’ll be 62. When you’re 50, she’ll be 72. Not saying that’s a bad thing, just stating the fact. How do you feel about this?
The difference between dating a young girl and a woman aged 42? Just stating the obvious, she will be more mature and will bring more to the relationship. What does she see in you? How do you view one another? As equals?
There is nothing in canon law or the discipline of the Church that prohibits age differences in marriage. It would be simply an issue of prudence and looking at your own mutual circumstances.
But all you have done is simply to ask her out. You are asking the right questions — too many people just date for the sake of dating, with partners they would never think of marrying. I’ve never been in favor of that. Very often one partner’s feelings will get way out in front of the other partner’s. Enjoy your date and hope things go well.